C#: Intercept the close button of the Form window

 I created this window from the parent window. I don’t want to create it every time, so I change the closing action to hide the window every time.

Just show it every time you want to use it.

namespace BiDaLock57L
{
    public partial class MakeCardForm : Form
    {
        public MakeCardForm()
        {
            InitializeComponent();
        }



        //遍历msg，确定是x掉的，类似MFC
        protected override void WndProc(ref Message m)
        {
            var WM_SYSCOMMAND = 0X112;
            var SC_CLOSE = 0XF060;
            if (m.Msg == WM_SYSCOMMAND && m.WParam == (IntPtr)SC_CLOSE)
            {
                MessageBox.Show("X 被按下了");
                //this.Hide();
                return;
            }
            base.WndProc(ref m);
        }
    }
}